Grinding wheels



'July 9, 1957 A. A. MILLER GRINDING WHEELS 3 sheets-sheet 1 Filed July25,- 1956 Fis. 2.1*

rrae/YE/ July 9,1957 v A. A. MILLER 2,798,342

. L Y l GRINDING WHEELS Filed .my 25. 195e 5 sheets-sheet s GRINDINGWHEELS Arthur'v A. Miller, McHenry, lll., assigner to Lou C. Casanov,Waukegan, Ill., and himself Application July 25, 1956, Serial No.600,019

3 Claims. (Cl. 51-192) My invention relates to improvements in grindingwheels.

My invention relates more particularly to a grinding wheel provided withan air cushioned tread portion.

Grinding wheels of the type to which this invention relates include aring or band of abrasive such as sandpaper or the like mounted on theperiphery or tread por tion of the Wheel, the tread portion beingcomparatively hard rubber, but so constructed that a certain amount ofresiliency is given to the sanding surface of the Wheel.

One of the principal objects of the present invention is to provide arelatively simple and inexpensive wheel of this sort that is made of arelatively small number of parts that are easily assembled to form astrong and sturdy device.

During the use of a sanding wheel, the wheel is caused nited Statesarent l tightening the abrasive band B on the same.

to rotate at a relatively high velocity and the article to be sanded isapplied against the sanding surface of the wheel. Due to the frictionbetween the sanding surface of the wheel and the article appliedthereto, there is a constant tendency for the abrasive band forming thesurface of the wheel to creep or move circumferentially about the same.This movement is prevented in the device forming the subject matter ofthe present invention in a manner to be described hereinafter.

In one form of the invention the tread portion is mounted so that acomparatively high velocity the same is permitted to expand, thustightening the abrasive band more effectively about the same. In anothertype of construction which forms part of this invention, the treadportion is provided with air under pressure to expand or move the sameout sufficiently to effectively grip the abrasive band and preventcreeping or circumferential movement of the same on the wheel.

Another object of the invention is to 'so construct the mounting orsupporting plates with air holes so that heat which is generated by agrinding action may be dissipated through the same during operation.

Other objects and advantages will be more apparent from the followingdescription wherein reference is had to the accompanying drawings, uponwhich:

Fig. 1 is a plan View of an abrasive Wheel mounted in driving relationto an electric motor;

Fig. 2 is a front view thereof;

Fig. 3 is a cross-sectional view thereof taken on the line 3-3 of Fig.2;

Fig. 4 is a similar cross-sectional view thereof showing a modified formof the invention; and

Fig. 5 is a cross-sectional View showing a further modified form.

In the embodiment of the invention which I have chosen to illustrate anddescribe the same, I provide a driving motor 10 which has a shaft hub 12through which a driving shaft 14 extends, the shaft being screwthreadedat the end to receive a locking nut 16.

The grinding wheel may include a pair of mounting plates 18 and 20generally similar to disc wheel members, having openings 23 therein toreceive the shaft 14.

The mounting plates 18 and 20 are also provided with facing peripheralgrooves 22 and 24 to clamp over circular ridges 26 and 28 formed in sideWall portions 30 and 32 of the tread member 34. The mounting plates 1Sand Z0 are also provided with a circular row of openings 36 and 38 toreceive fastening bolts 40 which also extend through aligned openings 42in the side wall portions 30 and 32 of the tread 34.

The tread 34 which is made of rubber, has the inner faces of the jsidewalls 30 and 32 vulcanized together at 46 around the inner opening 48 inthe same, so that when these walls are vulcanized together the airWithin the same is trapped and sealed therein, forming in effect a lowpressure tire construction.

In the embodiment of the invention shown in Fig. 3 I have also providedan annular ridge 50 in each of the side walls 30 and 32, so that whenthe grinding wheel is subjected to a comparatively high rotationalspeed, centrifugal force will tend to swing out the tread portion 52thereof to a slightly larger diameter, thus effectively The side Walls30 and 32 are contained Within the generally arcuate extensions 18a and20a of the mounting plates 18 and 20 to a point adjacent the treadportion 52 thereof.

' In the embodiment of the invention shown in Fig. 4, I have providedthe vulcanizing 46 between the inner surfaces of the side walls 30 and32 of the tread portion of the wheel to a point beyond the bolt members40, and provide an air valve 60 communicating with the chamber 62therein, the air valve passing through one of a plurality of openings 66in the mounting plate 20, the mounting plate 1S also having concentricrows of Openings 66 therein.

With this construction sufficient air pressure can be pumped into thechamber 62 to securely lock the abrasive band B on the periphery of thetread portion of the grinding wheel so that the same may be used forgrinding at comparatively low speeds if desired. With the provision ofthe concentric rows of openings 66 in both of the mounting plates 1S and20, heat generated in the rubber of the grinding wheel can be dissipatedto the atmosphere so that the grinding wheel is capable of longer useand will not become heated during operation.

In Fig. 5 I have shown a modified form of the invention wherein I employa cylindrical adapter 15, the adapter being of the desired width for thedesired width of the grinding wheel required for a particular job. Forthis purpose also longer bolts 40a are used as well as a longer shaft14a from the motor 12. It can be seen that the mounting plates 1S and 20are the same as those employed in the other embodiments of theinvention, and the tread 34 also has the same type of side walls 30a and32a with the tread portion 52a of the desired width required for theabrasive band B to be used. The side walls 30a and 32a are alsopreferably provided with one or more annular ridges 50a so that when thegrinding wheel rotates at a comparatively high speed centrifugal forcewill tend to swing out the tread portion to effectively tighten theabrasive band upon the same. Thus for various widths of abrasive bandsvarious Widths of adapters 15 may be employed, depending entirely uponthe type work to be done thereby.

From the above and foregoing description it can be seen that I haveprovided a grinding wheel constructed of comparatively few parts; alsoby the use of the ridges 26 and 28 in the rubber side walls of the treadportion and their containment in circular grooves in the mountingplates, together with the circular row of bolt members 40, the completeassembly is effectively held together and can not be easily broken orbecome out of order.

While I have illustrated and described a preferred embodiment of theinvention and modifications thereof,

it will be apparent to those skilled in the art that changes andmodifications may be made in the exact details shown and I do not wishto be imited in any particular; rather what I desire to secure andprotect by Letters Patent of the United States is:

1. An abrasive wheel of the class described comprising a mounting shaft,a pair of similarly shapedrmounting plates facing each other on saidshaft, said plates each having a flat disc portion and an axially andradially turned curved portion terminating in a portion parallel to saidat disc portion, a rubber tread member having a comparatively rigidperipheral edge, thin side walls transverse to said edge, said sidewalls having an axial opening therethrough and a circular ridgeconcentric to said axial opening and adjacent thereto, said side wallsextending inwardly from said peripheral edge and adapted to flex to lieagainst and be positioned against the facing lsides of said mountingplates, each of said mounting plates having a circular groove therein toreceivey a circular ridge of each of the side walls of saidV treadmembers, and an abrasive band secured about the peripheral edge of saidtread member.

2. An abrasive wheel of the class described comprising a mounting shaft,a pair of similarly 'shaped mounting plates facing each other on saidshaft, said plateseach having a flat disc portion and an axially andradially turned curved portion terminating in a portion parallel to saidflat disc portion, a rubber tread member having a comparatively rigid'peripheral edge, thin side walls transverse to said edge, said sidewalls having an axial opening therethrough and a circular ridgeconcentric to said axial opening andadjacent thereto, said side wallsextending inwardly from said peripheral edge and adapted to flex to lieagainst and be positioned against the facing sides of said mountingplates, each of 'said mounting plates having a circular groove thereinto receive a circular ridge of each ofthe side walls of said treadmembers, and an abrasive band secured about the peripheral edge of saidtread member, the inner edges of the thin side walls of 'said treadportion being vulcanized together to form an air-tight circular chamber.

3. An abrasive wheel of the class described comprising a mounting shaft,a pair of similarly shaped mounting plates facing each other on saidshaft, said plates each having a flat disc portion and an axially andradially turned curved portion terminating in a portion parallel to saidflat disc portion, a rubber tread member having a comparatively rigidperipheral edge, thin side walls transverse to said edge, said sidewalls having an axial opening therethrough and a circular ridgeconcentric to said axial opening and adjacent thereto, said side wallsextending inwardly from said peripheral edge and adapted to flex to lieagainst and be positioned against the facing sides of said mountingplates,'each of said mounting plates having a circular groove therein toreceive a circular ridge of each of the side walls of said treadmembers, and an abrasive band secured about the peripheral edge of saidtread member, the inner edges of the thin side walls of said treadportion being vulcanized together to form an air-tight circular chamber,one of said side walls having an air valve by means of which air underpressure may be introduced into said chamber.

References Cited in the file of this patent UNITED STATES PATENTS

